Bacterial Immunity and Toxic Shock

Question 1

Extracell bacteria

Answer 1

Staph aureus
Strep pyo/pneumo
E coli 
N mening
Pseudo aeru
Haemophilius influenz

Question 2

Evasion of complement by extracellular

Answer 2

POlysaccharide capsule (not staph)
LPS resists activation
Enzymes degrade complement

Question 3

Evasion of phago by extracell

Answer 3

Polysacch capsule resist
Proteins directly inhibit
Proteins suppress chemotaxis
Enzymes block lysosomal killing

Question 4

Evasion of antigen recognition by extra cell

Answer 4

LPS variation of patterns...can increase activation of things 
LPS resists recognition 
Antigenic disguises (fibrin)
Antigenic variation resists prior Ig binding

Question 5

Suppression of immune response by extracell

Answer 5

Enzymes that destroy leukocytes

Block antibody opsonization

Question 6

IMmune system evasion by extracellular

Answer 6

Biofilms blocks antibiotics and prevents recognition

Question 7

INtracellular bacteria

Answer 7

Legionella 
Myo tuberculosis 
Listeria
Salmonella 
Shigella
Chlamydia 
Rickettsia 
Mycoplasma pneumo

Question 8

Subversion of phagocytes by intracellular

Answer 8

Escape from phagosome (disrupt the membrane)
Block phago-lyso fusion
Survive within the phagolysosome (inactivates ROS)

Question 9

LPS

Answer 9

Endotoxin
Triggers TNFalpha and IL1 production
Binds to TLR (Triggers NFkB which recruits more inflammatory cells)
Modified LPS in Psuedo Aeruginosa cleaves receptors to increase NFkB

Question 10

AB exotoxins

Answer 10

B unit binds to receptors

A unit goes into the cell to act on target protein

Question 11

Other types of exotoxins

Answer 11

Membrane pore-forming (insert and lyse…widespread DAMP)
Hydrolytic enzymes (elastase, etc….facilitate invasion and increase DAMP)
Superantigens

Question 12

Normal helper T activation

Answer 12

MHC class 2 binding…Need CD28/B7 costimulatory

Question 13

Superantigen

Answer 13

Does not require APC processing…binds Vbeta portion of TCR and directly binds MHC2 molecules on APCs…activates tons of helper T cells

Question 14

Stretococcal toxic shock syndrome mechansim

Answer 14

Group A strep shes M protein in blood…M complexes with fibrinogen…Complex binds to integrins on PMNs….PMNs adhere to endothelium and degrade…Endothelial damage and edema

Question 15

Staph vs strep toxic shock

Answer 15

Strep - soft tissue necrosis, myonecrosis, resp failure (more deadly)
Staph - Rash, vomiting, diarhhea (less deadly)

Staph - 50/50 menstrual other cases
Strep - all skin, pneumo or bacteremia

Both have fever, hypotension and disorientation